1. Field of the Invention
The present invention relates to exercising machines, particularly to exercising machines of the type using resilient loading elements.
2. Description of Prior Art
Nowadays various types of exercising machines and devices are available on the market. One conventional exercising device, shown in U.S. Pat. No. 4,205,839 to M. Best, issued June 3, 1980 comprises a pair of cords which pass over sheaves in pulley blocks carried on a rigid member pivotally attached to a fixed support. One end of each cord is hand held, and the other end is provided with foot stirrups for the user's feet. In operation, the resistance or load for the arm muscles is provided by the force applied from legs, and vice-versa. An exercising device of this type, however, does not possess versatility and cannot be used for exercising and developing various types of a person's body muscles. Furthermore, it is not a self-contained device: i.e., it cannot be utilized in a variety of locations since it requires an appropriate fixed or stationary support.
Another known exercising device is disclosed in U.S. Pat. No. 4,185,816 to M. Bernstein, issued Jan. 29, 1980. This device is a sit-up exercising apparatus which is adapted to be utilized in conjunction with a door. The apparatus comprises a U-shaped frame which is inserted beneath the door and which is provided with means for rigid attachment to the door. The U-shaped frame is used as a support for a bracket carrying a bar; the bar is used, in the course of exercising, as a foot support. This device also possesses a number of disadvantages, the main ones being lack of versatility and a restricted field of application since it is suitable only for the development of abdominal muscles.
Another exercising machine of a self-contained type, which is now produced by Marcy Fitness Products under the trademark BODYBAR, is illustrated in "1984 Spring and Summer Supplement Consumers Catalog", (Consumers Distributing, 205 Campus Plaza, Edison, N.J. 08837), CD-3, page 149.sup.3, items C and D. This apparatus comprises an upright rigid frame which is used for guiding an adjustable weight attached to a cable which is threaded through a pulley system. The free end of the cable is attached to a hand grip. The apparatus is provided with a removable bench which carries a leg support connected to the weight through a cable and a lower pulley. Although this apparatus is self-contained, it cannot be used universally for developing various groups of muscles, as well as for aerobic exercises. For example, it cannot be used as a bicycle simulator. Moreover, this device is heavy, occupies much space, is expensive to manufacture, and is incovenient for transporation and storage. Since the resistance is provided by weights, this apparatus cannot be used in a spaceship for astronauts' training under weightlessness conditions.
Some conventional exercisers are based on the principle of gas-filled cylinders. One such device, which is produced by M. & R. Industries, Inc. (9215-151st Avenue NE, Redmond, WA 98052) comprises a frame with a slidable seat and foot supports. It is provided with a pair of air cylinders attached to both sides of the frame and corresponding pivotal handles which are connected to the piston rods of the cylinders' pistons. This exerciser can simulate rowing as well as other exercises: a user swings the pivotable handles to displace air from the cylinders. This device lacks versatility and provides but a one-directional resistance. Thus it does not provide continuous loading and requires extra time for returning the pistons to their original positions, resulting in poor efficiency.